Zakriah

A druid mentioned briefly in The Light Fantastic, Zakriah was part of a group of druids running a concentric ring stone circle on the Vortex Plains, and seemingly in charge of its operation.

He attempted, and failed, to solve the problem of the circle, running the Chant of the Trodden Spiral (a chant program which was designed for concentric rings), predicting sunrise three minutes early. This is considered a major problem in druidic circles (no pun intended) and so he had to call in Belafon, in the role of computer hardware consultant.

Both Belafon and Zakriah failed to find any problems in the circle, and so determined that the universe had gone wrong- which it had.